The cost that a hosting provider charges a customer for the usage of an instance of a virtual machine provided by the hosting provider is often determined by a number of variables. For example, the amount or storage space assigned to the virtual machine, the amount or random access memory (RAM) assigned to the virtual machine, as well as the number of physical or virtual processors assigned to the virtual machine may all impact the cost charged by the hosting provider. Moreover, each of these resources may have different tiers of performance with different associated costs. For example, a virtual machine may have the option of having one or more virtual disks stored on an array of high-bandwidth, low-latency solid state drives (SSDs) or high-capacity, but lower bandwidth and higher-latency hard disk drives (HDDs). The hosting provider may charge different rates for usage of SSDs or HDDs for storage of a virtual machine's virtual disks.
However, some types of resources consumed by virtual machines can be difficult to accurately track. For example, tracking the amount of storage used by virtual machines that have been assigned one or more Raw-Device Mapping (RDM) disks and charging appropriately for it faces several problems. First, the mapping file provided by the RDM to the virtual machine may reside in a different data store than the underlying logical device that stores the data. For instance, the mapping file may be located on an array of HDDs while the mapped data may be stored on an array of SSDs. Second, the different data stores may have different costs associated with their usage.